1. Field of the Invention
The present invention is directed to explosive mixes, and more particularly lead-free and non-toxic explosive mixes.
2. Brief Description of the Related Art
Various lead-free priming mixtures for use in ammunition have been disclosed over the years. For example, a nontoxic, noncorrosive priming mix described in U.S. Pat. No. 4,675,059 is one such composition. This priming composition contains diazodinitrophenol, also known as dinol or DDNP, manganese dioxide, tetrazene and glass. Another example of a nontoxic priming mixture is disclosed in U.S. Pat. No. 4,963,201, issued to Bjerke et al. This composition comprises dinol or potassium dinitrobenzofuroxan as the primary explosive, tetrazene as a secondary explosive, a nitrate ester fuel and strontium nitrate as the oxidizer. U.S. Pat. No. 5,993,577 to Erickson et al. discloses a lead-free priming composition made from diazodinitrophenol (DDNP), a low percentage of tetrazene, and a high percentage of an abrasive such as ground glass.
Many of the leadfree mixes based on dinol (DDNP), despite being “leadless”, still contain toxic heavy metals such as barium and antimony. These are present in the fuels and oxidizers traditionally used in priming mixtures. Other fuels and oxidizers have also been employed, but many of them suffer from hygroscopicity, inherent moisture retention, sensitivity to moisture, unavailability, instability, and inherent processing difficulties.
Bismuth compounds have been used in various medications and personal care compositions. For example, U.S. Pat. No. 6,426,085 to Athanikar discloses use of bismuth-containing compounds in topical oral dosage forms for the treatment of halitosis. U.S. Pat. No. 6,379,651 to Athanikar discloses treatments with bismuth compounds, other antibacterial compounds, and/or antibiotics in oral-topical and peroral dosage forms to eradicate H. pylori order to improve the ulcer cure rate and prevent ulcer relapse. U.S. Pat. No. 6,372,784 to Athanikar discloses a method for treatment of corneal and dermal wounds by administering bismuth compounds in topical dosage forms. In addition, bismuth has been demonstrated to be an accepted non-toxic material used in non-toxic shot for waterfowl hunting.
Bismuth subnitrate (also known as bismuth nitrate basic,) has been disclosed for use as an antacid, and in compositions for regulating wrinkles or atrophy in mammalian skin (See for example U.S. Pat. Nos. 5,883,085; 5,837,697; 5,811,413; 5,795,879; and 5,780,458).
U.S. Pat. No. 6,478,903 to John, Jr. discloses a non-toxic primer mix including both bismuth sulfide and potassium nitrate as the pyrotechnic portion of the primer. However, bismuth subnitrate is not disclosed.
What is needed in the art is a lead-free, non-toxic priming composition that reduces or eliminates toxic heavy metals such as antimony and barium, yet is economical, easy to produce, and is free from the above-mentioned problems of hygroscopicity, inherent moisture retention, and moisture sensitivity. The present invention is believed to be an answer to that need.